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Topic: Float test (Read 1337 times)

It looks as if the photo was taken with a Coke bottle, but it's really a bad cell phone pic taken in the dark.

My homegrown starter culture was removed from the fridge and prepared for use (threw some out/fed/vigorously whisked). Out of the fridge it has an amazing scent: think ripe granny smith apples with a trace of malt vinegar. I'm no SD expert, nor do I play one on TV, so I'm curious as to what others think of this smell... So, about 3 hours after the prepping its risen and fallen, I plopped a spoonful into water and it floats, albeit groggily...Looking fwd to working with the 85% hydrated dough this evening.

It looks as if the photo was taken with a Coke bottle, but it's really a bad cell phone pic taken in the dark.

My homegrown starter culture was removed from the fridge and prepared for use (threw some out/fed/vigorously whisked). Out of the fridge it has an amazing scent: think ripe granny smith apples with a trace of malt vinegar. I'm no SD expert, nor do I play one on TV, so I'm curious as to what others think of this smell... So, about 3 hours after the prepping its risen and fallen, I plopped a spoonful into water and it floats, albeit groggily...Looking fwd to working with the 85% hydrated dough this evening.

Smell alone means little for starters, especially those with lower hydrations (< 75% or so), as they retain a larger amount of the aromatic volatiles produced during fermentation than their wetter counterparts. Many of the smells in a storage container or inside a starter accumulate early during the fermentation cycle and can later mix with those created later on. It's not that smell should be discounted but that judgments made about the state of a starter aren't necessarily as revealing as most people think, especially with fermentations lasting longer than 10 hours. What's more, the aromas generated for a maintenance starter versus a dough starter versus a final dough are, for the most part, different, especially during the latter, when there's an introduction of salt and when the fermentation times are (usually) shorter.

But orchard fruit and acid are not bad smells to have!

The float test, by the way, also tells little; it simply lets amateur bakers know there's sufficient carbon-dioxide production in a starter to raise a dough, and should be seen as a (somewhat) reliable test for the earliest point at which a dough starter should be used but not necessarily the optimal, depending upon what you're trying to achieve.

I especially found your last paragraph interesting. About the earliest point and optimal points, could you comment more on the latter?

The float test answers the question, like the old Letterman skit, "Will it float?" Nothing more. That is, has there been sufficient carbon-dioxide production from the culture so it remains buoyant in water? This sort of thinking about sourdough uses external signs only; it tells you very little about what's going on inside the dough.

"Optimal" is a relative term here; it means different things to different people. The Chad Robertson method is based around his penchant for wanting to use "young" starters for a dough, when a culture's in its early log stages, which is great for CO2 production but not necessarily other considerations, such as dough strength, flavour, etc. The float test is also employed because it's harder to accurately judge a starter by sight alone when maintained at 100% hydration.

A dough's pH is a much more revealing measurement for sourdough bakers and pizzamakers than other parameters, like measuring CO2 output, time, etc.

Out of curiosity, do you measure the pH of your culture and doughs and, if so, what values do you look for?

Peter

Ian,

I would also be interested in knowing what Peter asked since I am doing pH experiments. I also wonder if it matters what the pH of the water that is fed to the starter and also about what kind of flour is best to be used to feed cultures.

Out of curiosity, do you measure the pH of your culture and doughs and, if so, what values do you look for?

Peter

Yes, I do, and use pH to establish three basic parameters for any dough, including my maintenance starter, dough starter and final doughs. The first is to establish a standard baseline after the initial mix, which varies per dough, quite obviously, based upon the amount of flour prefermented. I use this to ensure, first, that the correct pH was obtained for the pre-dough going into the mix (the starter) and also to check to see mixes were correct (in this scenario I use it less often). Second, I use it to establish the final pH for doughs, in particular starters, which I never want to go below 4.0 / 3.9 before refreshment, with my maintenance starter in particular. (This is because I am aiming to maintain a particular culture.) Lastly, I establish a pH that, when coupled with FDT out of mix, dough temperature during fermentation and time spent in bulk, will let me know when it's time for dough division; again, as before, this number varies for each dough but rarely does not go below 4.5 / 4.4, when "enhanced proteolysis" occurs.

If used for a predictive model, the results become more complicated, though. pH means nothing without such considerations as temperature, time and substrate (ash content). Here, theoretically-predicted data would need to be reinforced with real-world statistical data, especially hard since most American flours do not adequately list ash content of their flours, fermentation temperatures tend not to be constant, and so on.

I would also be interested in knowing what Peter asked since I am doing pH experiments. I also wonder if it matters what the pH of the water that is fed to the starter and also about what kind of flour is best to be used to feed cultures.

Norma

pH of water matters less than you might imagine for starter cultures; starters prefer doughs that are more alkaline than acidic to begin with. The pH of water can have other effects on the quality of a dough out of initial mix, quite obviously, but I do not think that's the question being asked.

As per flour, there's one basic rule of thumb, especially for maintenance starters: the more whole grain and fresher it is, the better. Lactic-acid bacteria, Lb SF in particular, evolved to ferment and utilise every fraction of the wheat, rye, spelt and/or teff kernel as part of its metabolic life-cycle. Flours of lower extraction favour yeast fermentation due to greater sugar content and because of their low buffering capacity. This is where grain mills come in handy. Using fresh, whole-grain flours has a noticeable difference on nutrition, flavour, rheology, a culture's activity, etc.

Yes, I do, and use pH to establish three basic parameters for any dough, including my maintenance starter, dough starter and final doughs. The first is to establish a standard baseline after the initial mix, which varies per dough, quite obviously, based upon the amount of flour prefermented. I use this to ensure, first, that the correct pH was obtained for the pre-dough going into the mix (the starter) and also to check to see mixes were correct (in this scenario I use it less often). Second, I use it to establish the final pH for doughs, in particular starters, which I never want to go below 4.0 / 3.9 before refreshment, with my maintenance starter in particular. (This is because I am aiming to maintain a particular culture.) Lastly, I establish a pH that, when coupled with FDT out of mix, dough temperature during fermentation and time spent in bulk, will let me know when it's time for dough division; again, as before, this number varies for each dough but rarely does not go below 4.5 / 4.4, when "enhanced proteolysis" occurs.

If used for a predictive model, the results become more complicated, though. pH means nothing without such considerations as temperature, time and substrate (ash content). Here, theoretically-predicted data would need to be reinforced with real-world statistical data, especially hard since most American flours do not adequately list ash content of their flours, fermentation temperatures tend not to be constant, and so on.

pH of water matters less than you might imagine for starter cultures; starters prefer doughs that are more alkaline than acidic to begin with. The pH of water can have other effects on the quality of a dough out of initial mix, quite obviously, but I do not think that's the question being asked.

As per flour, there's one basic rule of thumb, especially for maintenance starters: the more whole grain and fresher it is, the better. Lactic-acid bacteria, Lb SF in particular, evolved to ferment and utilise every fraction of the wheat, rye, spelt and/or teff kernel as part of its metabolic life-cycle. Flours of lower extraction favour yeast fermentation due to greater sugar content and because of their low buffering capacity. This is where grain mills come in handy. Using fresh, whole-grain flours has a noticeable difference on nutrition, flavour, rheology, a culture's activity, etc.

Ian,

Thank you for your helpful post. I am going to try an organic flour to feed the Ischia culture.

Lastly, I establish a pH that, when coupled with FDT out of mix, dough temperature during fermentation and time spent in bulk, will let me know when it's time for dough division; again, as before, this number varies for each dough but rarely does not go below 4.5 / 4.4, when "enhanced proteolysis" occurs.

Please post an example of the math behind this calculation.

Logged

"We make great pizza, with sourdough when we can, commercial yeast when we must, but always great pizza."Craig's Neapolitan Garage

To be honest, I'm not sure I understand the nature of the request. To answer this specifically, I have built my own calculators using spreadsheets and the wonderful help of those more mathematically-inclined than myself (with lots of back and forth, tweaking, etc.) to arrive at something that generates, for me, somewhat predictable results. The basic equations we used as starting points were the same you can find in several of the studies outlining Lb SF's known growth conditions, which I assumed you used for your sourdough calculator, too. There are a few others we used to cobble together a working model plus a lot of real-world trial and error from my end. You could probably speak to this area better than I could, as I was merely the instigator, since math isn't my strong suit!